1. Field of the Invention
This invention relates to digital sound synthesizers, and more particularly, to such synthesizers which are useful for synthesizing, for example, the real time production of musical sounds.
2. Description of the Prior Art
The synthesizer to be described herein will be described, without limitation on its possible applications, in terms of a music synthesizer because that is one of the more difficult applications thereof. Such machines are, however, also known to be useful, e.g., for performing such functions as speech synthesis and sound effect synthesis.
It is known in the art to synthesize musical sounds which either are substantially similar to those of conventional musical instruments, or are different from the sounds of such instruments, without resort to such conventional instruments. The equipment used for synthesizing takes many forms. In one of those forms a performer actuates an input transducer to define a selected note and its duration in a composition. Such transducers may include, e.g., a keyboard, slide switches, joy sticks, or others. A computer is used to translate signals from the input transducer into differently coded signals representing the same information but in terms of corresponding signals for controlling a synthesizer circuit to generate signals representing the selected note in accordance with a performer-selected instrumental voice. "GROOVE--A Program to Compose, Store, and Edit Functions of Time" by M.V. Mathews and F.R. More, Communications of the ACM, Vol. 13, No. 7, December 1970, pages 715-721, indicates one such system using an undisclosed analog synthesizer.
Although the known type of computer translation can be readily carried out on a real time basis, synthesizers heretofore available have been unable to be controlled for operation on a like-real-time basis for producing sound approaching the complexity of sound producing sound approaching the complexity of sound produced by a small orchestra, e.g., 10 to 15 instruments, playing any of various kinds of music. Such an involved performance is herein called a score-real-time, or soundreal-time, operation that would provide essentially immediate audible feedback so that a composition can be played in real musical time by the performer.
Clearly, there are existing synthesizing structures, e.g., the Mathews et al. GROOVE-controlled system, available which can produce score-real-time outputs. However, those systems are subject to various infirmities such as working in terms of unique sounds lacking the richness of sounds of conventional musical instruments, or requiring magnificent analog or digital structures which involve room-size installations and are conveniently operable by most artistic performers only with close cooperation of skilled technicians.
Most prior art synthesizers have utilized concepts such as using separate circuit modules for different voices or even different note ranges. There have also been speculative suggestions in the literature for using separate modules for executing different ones of the constituent functions involved in particular synthesizing algorithms and of the possibility for time-sharing some modules. However, the enabling information as to such speculative suggestions has not been similarly available for operative apparatus.
It is, therefore, one object of the present invention to improve sound synthesizing systems.
It is another object to reduce the size and cost of synthesizer systems.
A further object is to synthesize more voices of a musical score than had been heretofore possible on a substantially simultaneous score-real-time basis.